1. Field of the Invention
The present invention relates to cores for inductors, transformers and like elements used in high frequency power conversion, and to a composition for making said cores.
2. Background Information
Magnetic materials such as ferrites and powered iron are formed into cores for magnetic devices, inductor and transformer cores, for use in, amongst other things, power converters. Ferrites are mixed compounds of ferromagnetic oxides (Fe2O3) and several oxides of bivalent metals such as Nickel Oxide (NiO), Manganous Oxide (MnO) and Zinc Oxide (ZnO). They exhibit low loss and good high frequency operation characteristics. Powdered irons, such as Molydbenum Permalloy Powder (MPP), are mixed with Nickel and Iron to provide magnetic materials for power conversion applications.
The design of a magnetic device depends on such factors as the permeability, loss factor, and size and shape of the core. The loss in a magnetic device usually accounts for 30-40% of the total loss in a power converter.
Conventional magnetic materials suffer from a number of disadvantages including limited size, brittleness, high loss and high cost. One of the typical problems is that for application in high power conversion, over 20 kW, the magnetic materials for device cores are expensive and difficult to form into the desired shape.